The DataRelation class
represents a parent-child relationship between two
DataTable objects in the same
DataSet. The DataRelation can
be used as a navigational aid, or it can enforce relational integrity
and cascade deletes or updates. In the latter case, the constraints
are actually applied by the ForeignKeyConstraint
class, which the DataRelation creates
automatically when added to a DataSet.
As with all disconnected data classes, the
DataRelation isn't specific to
any provider. DataRelation objects must be created
manually; the provider can't generate them based on
the information in the data source.